Apparent total and ileal digestibility of rice bran with or without multicarbohydrase and phytase in weaned piglets

摘要

In the first 2 weeks after weaning, the piglets' digestive system cannot efficiently digest the new diet with vegetal ingredients. This study evaluated the effects of multicarbohydrase - MC (700 U alpha-galactosidase, 2200 U galactomannanase, 3000 U xylanase and 22 000 U beta-glucanase per kilogram of diet), and phytase - Phy (500 phytase units - FTU/kg of diet) supplementation on the nutritive value of rice bran (RB) in weaned piglets. Twenty-five weaned piglets, 21 days old, were individually caged to determine the apparent digestibility of dry matter (DM), crude protein (CP), ash, digestible (DE), metabolisable (ME) energy, methane production, as well as apparent (AID) and standardised (SID) ileal amino acid digestibility in RB. Treatments were applied in a completely randomised experimental design with a 2 x 2 (0 and 200 mg/kg MC; 0 and 50 mg/kg Phy) factorial arrangement. An additional group of five piglets was fed a corn-basal diet (BD) during apparent digestibility evaluation of nutrients and a 5% casein-corn starch basal (BD 1 ) diet during apparent and standardised ileal digestibility (SID) of amino acid evaluation. Ileal digesta were collected at slaughtering (38 days old). Test diets were made by mixing the basal diets and RB 7: 3 (w/w), with or without MC, Phy-or the combination. There was a positive interaction (P < 0.05) between MC and Phy-in the balance of CP and energy. An effect of Phy (P < 0.05) was observed on DM, CP and ash digestibility, whereas MC only improved N retention (P < 0.05). The pronounced effect of Phy-on ash digestibility of RB confirmed what was expected; however, it had no equivalent effect on amino acid digestibility. Based on literature data, the nutrient balance and digestible energy of RB without enzymes were lower than those using older pigs; AID and SID values for indispensable amino acids were 39 and 17% lower, respectively. The combination MC + Phy-showed an effect (P < 0.05) on Ile, Leu, Thr, Trp-and Val-digestibility. Isolated or combined, the enzymes increased the AID and SID averages of all amino acids in RB (P < 0.05). Enzyme combination provided a positive synergy for energy and protein digestibility of RB. The MC + Phy-RB test diet produced less methane, followed by Phy-and MC diets.